1. Field of the Invention
The invention relates to a method for the filling and flushing of a blood tube set, comprising a pump segment for a blood pump, an arterial line connected to an inlet of a dialysis machine and a venous line connected to an outlet of a dialysis machine, via a substituate line.
2. Description of the Related Art
Blood tube sets of this type are used in extracorporeal blood therapies, e.g. in hemodialysis, and form the extracorporeal blood circuit in this process. As a rule, disposable articles are used as the arterial and venous lines which are packed in a sterile manner and have to be filled and flushed prior to the treatment. This filling and flushing of the blood tube set is also called priming and serves to avoid the contact of blood with air in the extracorporeal therapy. In this connection, the blood tube system made as a disposable system is filled with substituate before the patient is connected for treatment so that the extracorporeal system is practically air-free after the priming. After the filling and flushing of the tube system, venous and arterial lines are typically connected to one another such that the substituate can circulate in this circuit of arterial line, dialyser and venous line until the patient is connected to the system. After the connection of the patient, the substituate is displaced by the inflowing blood such that a possible contact of the blood with air is reduced to a minimum.
Methods are known for the filling and flushing of blood tube sets using bags with a physiological solution and corresponding bags for the collection of the used solution. In this connection, a bag with saline solution is typically connected to the arterial line and the latter is filled. After the filling of the arterial line, the blood pump is now used to also fill and flush the venous line. For this purpose, the pump segment of the blood tube set, a tube section with specific properties, is inserted into the blood pump, typically a peristaltic pump or a roller pump, such that the blood pump can pump saline solution into the venous line via the pump segment.
To automate the filling and flushing process as much as possible, a method was proposed in EP 831 945 B1 in which a T connector is used to short-circuit the arterial line and the venous line for filling and flushing and to connect them to a bag to collect the used solution via the T connector. Furthermore, valves are necessarily provided in the proximity of the connector at the blood lines, that is at the arterial and venous lines, to control the filling and flushing process. First, in this process, the substituate is filled into the arterial line from a bag by the use of gravity. After the opening and closing of the corresponding valves, the liquid is thereupon filled from the arterial line into the venous line. After a further opening and closing of the corresponding valves, the substituate can then be circulated by the blood pump in the circuit of arterial line, dialyser and venous line. The attachment of the controllable valves to the blood tubing set is awkward and may not be forgotten in this process, additionally requires electrical and pneumatic connections and is prone to operating errors of the dialysis nurse, e.g. due to confusion or incorrect positioning of the valves. It is additionally necessary, before the start of the automatable procedure, to manually hang up a source with a sterile fluid (e.g. a bag with sterile saline solution) above the treatment machine, to pierce this source and connect it to the blood tubing set, with it having to be ensured that the valves have been correctly fitted beforehand and are closed. In addition, the valves must be controlled on the hardware side and software side for the automation of the valve actuation, with it simultaneously having to be ensured that none of the valves fail or are located in an incorrect closing position after the connection of the solution bag.